Answer:
The answer is 8 feet.
Step-by-step explanation:
Let x = height where the ladder hits the building
7 squared+x squared=25 squared
49+x squared=625
x squared=576
x=24 feet
Let x = distance from wall:
x^2 + 20^2 = 25^2
x^2 + 400 = 625
x^2 = 225
x = 15 feet
Answer:
π/10
Step-by-step explanation:
When we rotate the region about the y-axis, we get something that looks like a volcano, or a bundt cake. Instead of slicing this into flat washers, we'll slice it in concentric rings, or "shells".
Each shell has a radius x, a thickness dx, and a height y. The volume of an individual shell is:
dV = 2π r h t
dV = 2π x y dx
Since y = x² − x³:
dV = 2π x (x² − x³) dx
dV = 2π (x³ − x⁴) dx
The total volume is the sum of all the shells from x=0 to x=1.
V = ∫ dV
V = ∫₀¹ 2π (x³ − x⁴) dx
V = 2π (¼ x⁴ − ⅕ x⁵) |₀¹
V = 2π (¼ − ⅕)
V = π/10
4 / 30 = x / 75...4 drivers to 30 sq miles = x drivers to 75 sq miles
cross multiply
(30)(x) = (75)(4)
30x = 300
x = 300/30
x = 10 <== 10 drivers for 75 sq miles
The product of 14x25x4 is 1400 but I don't understand why you put use subtraction.